Alyssa Devin and Andrew Schmid

Student: Alyssa Devin and Andrew Schmid

Project: Characterization of the Lafayette College Hypersonic Expansion Tube

Institution: Lafayette College

Major: Mechanical Engineering, Economics

Advisor: Tobias Rossmann


The Lafayette College Hypersonic Expansion Tube is a state-of-the-art facility that allows for the simulation of airflow in a scramjet engine. The expansion tube can generate very high stagnation enthalpy Mach number flows for a short duration using moving shock waves. The moving shockwaves are generated and accelerated by the rupture of diaphragms which separate the varying initial pressures in four different sections of the tube. Simple inviscid theory can be used to generate a model, known as an X-t diagram, of the wave motion in the tube to determine flow quantities (velocity, temperature, and pressure) in the test section as a function of time.
An X-t diagram is a tool used to display time and position of all waves and gas interfaces within the expansion tube during a test. Viscous interactions, geometric expansion, and non-linear shockwave behavior all contribute deviation of expansion tube actual behavior from an easily calculable idealized model. This project is focused on the creation of an experimentally calibrated X-t Diagram which enables accurate predictions of real flow conditions for both current and future experiments. Initial pressures and pressure ratios will be varied to understand the non-ideal effects on shock wave formation, propagation and expansion. Using Schlieren Imaging, static and stagnation pressure measurements, and infrared gas temperature measurements of test gas arrival, flow conditions (temperature, pressure, and velocity) can be determined at all positions in the tube during the test time. Using this data and systematic testing of the expansion tube, the X-t Diagram then will be calibrated to reflect real conditions and can be used to predict the flow within the Expansion Tube for any set of initial conditions.

About Alyssa Devin

Alyssa Devin, is a senior at Lafayette College and a honors thesis student who will graduate in May of 2019. Alyssa will graduate with a Bachelor of Science Degree in Mechanical Engineering and a minor in Writing. Alyssa is passionate about aerospace research and has been involved with the Laboratory for Undergraduate Combustion and Hypersonics (LAUNCH) research on the Lafayette campus since the end of her sophomore year. Her research involves the Lafayette College Hypersonic Expansion Tube, a facility that allows the study of supersonic flight conditions and testing. Her work has helped characterize flow conditions within the expansion tube. Alyssa is a Head Resident at Lafayette College where she supervises a staff of twelve Residential Advisors. Upon graduation, Alyssa will be working at Lockheed Martin in the Rotary and Mission Systems Division in Syracuse, New York. There, she will be a part of the Engineering Leadership Development Program.

About Andrew Schmid

Andrew Schmid, is an Excel Research Scholar at Lafayette College pursuing a dual-degree in Mechanical Engineering (B.S.) and Economics (A.B.). His work in the Laboratory for Undergraduate Combustion and Hypersonics (LAUNCH), has focused on studying the hypersonic flow of argon. Andrew has also developed a solenoid-based firing sequence for the expansion tube facility. During his time as a member, and now Vice President, of the Lafayette College student chapter of the American Society of Mechanical Engineers (ASME), Andrew has led the Strato-Sat project team and organized community outreach events. In his free time, Andrew serves as the President of the Lafayette College Running Club, where he and fellow students run away from their problems.

Lehigh Engineering Undergraduate Research Symposium

Congratulations to the 2019 Undergraduate Research Symposium winners:

Read full coverage from this year's event here!